1 Answer
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You first check that its roots lie in $\mathbb{F}_{2^n}$ by computing $X^{2^n}$ mod the polynomial $p(X)$ and checking that you get $X$. Then you want to know that the roots don't lie in a subfield, i.e., that $p(X)$ is irreducible. So for each maximal divisor $d$ of $n$, compute $\text{gcd}(p(X),X^{2^d}-X)$ and check that you get 1. Then you want to know that a root of $p$ has maximal order. So for each maximal divisor $d$ of $2^n-1$, check that $X^d$ mod $p(X)$ is not 1. The hardest step is to find the maximal divisors of $2^n-1$, which requires the prime factorization of $2^n-1$. If you don't know that, then you are probably sunk.